This invention relates to a shift-time indicating system, in particular, for an over top mechanism or a sub-transmission for a motor vehicle which is operated by a hand-operated shift lever. The shift-time indicating system senses loading conditions of an engine to indicate an exact timing of gear shift to a driver, thereby enabling timely operation of the shift lever and effecting a decrease in fuel consumption.
There has been provided a transmission which is automatically shifted to an over top gear depending on the loading conditions of the engine. However, such transmission is complicated in its construction and expensive. Furthermore, in the transmission of conventional type in which shift to over-top or change-over of a sub-transmission is manually operated, shifting operation is carried out depending on human senses, such as by hearing the engine noises in order to perceive the loading condition.
Therefore, with the above manually operated speed changing gear, it is impossible, during high speed steady driving, to keep on selections of shift ranges which are most pertinent in relation to the fuel consumption, thereby defectively causing an increase in the fuel consumption.